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November Mid/Long Range Discussion


WxUSAF
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2 hours ago, nj2va said:

Apparently its more fun to post 384H OP temp anomaly maps. 

Maybe I missed a 384op map. I posted a 240 EPS anomaly map. This is the November long range thread not the purely “what’s the winter going to be” thread.  The long range looks warm for now. That was it. Posting a day 10 ensemble in early Nov means nothing for what winter will end up like. It does mean the current long range looks hostile to snow.  Oh well. It’s November. But I have had several warning level events by thanksgiving. I don’t expect one this year.  

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8 hours ago, Itryatgolf70 said:

Alot of forecasters may need to change their winter forecasts already with the MEI dropping:unsure:. I know its one of many factors though. Even JB should probably do it. The ones that have waited was probably a good idea

Too soon, same thing happened in 1986-87. It’ll probably go back up in the next month, but if it doesn’t, then I’ll probably consider updating my outlook. 

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42 minutes ago, Maestrobjwa said:

Alright please explain to us layman what the MEI is (and so if it screws us I can put it on a punching bag)

Multivariate ENSO index. Basically a more comprehensive way to measure the impact of ENSO on the ocean and atmosphere. The current MEI is basically “warm neutral” vs strong Nino pacific SSTs.

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Alright please explain to us layman what the MEI is (and so if it screws us I can put it on a punching bag)

It’s basically looking at more factors than your typical 3.4 anomalies. The mei is way out of whack(.3) compared to the oni 1.5
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2 hours ago, Ji said:


It’s basically looking at more factors than your typical 3.4 anomalies. The mei is way out of whack(.3) compared to the oni 1.5

But unless I am not following correctly, a lower MEI is a good thing, if we had an MEI that corresponded to a strong El Niño, the analog years are not good.  The El Niño analog years with a lower MEI are much better. 

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30 minutes ago, Weather Will said:

But unless I am not following correctly, a lower MEI is a good thing, if we had an MEI that corresponded to a strong El Niño, the analog years are not good.  The El Niño analog years with a lower MEI are much better. 

 

For KIAD, there is a weak positive correlation between snowfall and MEI. It's noisy and mostly a crapshoot, but we can clearly see a few things:

- If the MEI is less than -1.0 (stronger Nina), it gets very difficult for us to reach climo or above. Most often we end up with less than climo.

- If the MEI is greater than +1.0 (stronger Ninos), we likely get a warm winter overall and MAYBE with a HECS that pads snowfall totals. No HECS? Ratter.

- If the MEI is between -1.0 and +1.0, it really can go either way. 

Notice that if we are between +0.5 and +1.2 (which I prefer using as the cut off), our chances for a colder and snowier winter go up.

 

image.thumb.png.f5e5d89033b0071f9818319ffefb5645.png

 

MEI +1.2 or higher:

MEI-Tanoms_warm-greater-than-1.2.png.015c88ce133c3d3976547daeaf289b9a.png

 

MEI between +0.5 and +1.2

MEI-Tanoms_warm-but-less-than-1.2.png.8b80996ff5fe7a4f61c36968892e9a95.png

 

So this recent drop in MEI probably precludes us from getting over +1.2, which may be a good thing in avoiding a mild winter for the CONUS, but I think we will need to get a more favorable nino profile in the pacific to get a colder winter than the last 8 years.

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17 minutes ago, Terpeast said:

 

For KIAD, there is a weak positive correlation between snowfall and MEI. It's noisy and mostly a crapshoot, but we can clearly see a few things:

- If the MEI is less than -1.0 (stronger Nina), it gets very difficult for us to reach climo or above. Most often we end up with less than climo.

- If the MEI is greater than +1.0 (stronger Ninos), we likely get a warm winter overall and MAYBE with a HECS that pads snowfall totals. No HECS? Ratter.

- If the MEI is between -1.0 and +1.0, it really can go either way. 

Notice that if we are between +0.5 and +1.2 (which I prefer using as the cut off), our chances for a colder and snowier winter go up.

 

image.thumb.png.f5e5d89033b0071f9818319ffefb5645.png

 

MEI +1.2 or higher:

MEI-Tanoms_warm-greater-than-1.2.png.015c88ce133c3d3976547daeaf289b9a.png

 

MEI between +0.5 and +1.2

MEI-Tanoms_warm-but-less-than-1.2.png.8b80996ff5fe7a4f61c36968892e9a95.png

 

So this recent drop in MEI probably precludes us from getting over +1.2, which may be a good thing in avoiding a mild winter for the CONUS, but I think we will need to get a more favorable nino profile in the pacific to get a colder winter than the last 8 years.

So we're basically .2 away from being in the sweet spot of this composite... Attainable?

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1 hour ago, Maestrobjwa said:

So we're basically .2 away from being in the sweet spot of this composite... Attainable?

Absolutely. It could swing the other way next month, or take its sweet time into getting above 0.5 till January. 

But then again, I expected it to come in at 0.75 this month and I was wrong. So...

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2 hours ago, Weather Will said:

But unless I am not following correctly, a lower MEI is a good thing, if we had an MEI that corresponded to a strong El Niño, the analog years are not good.  The El Niño analog years with a lower MEI are much better. 

yes i didnt say it was a bad thing. It all but rules out out of the super ninos the capital weather gang kept hyping. No 2015,1997 or 1982 this season i believe

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Pretty good ensemble agreement on how the pattern develops going into Thanksgiving week with a much more Nino-like look to things.  Pattern shuffle starts with this big upper low crashing into the west coast around D8-9.

image.thumb.png.c35c62d6de1519643d04f2ef069033bb.png

image.thumb.png.94160d0a66e2e6b8d182abe07dfd6fd9.png

 

That serves to undercut the ridge in Canada and ridging expands over AK.  This doesn't look like a particularly cold pattern for us with a +AO/+NAO and the coldest air from the -EPO will dump out west first before coming east.  But it looks a lot more Nino-like and actually looks a fair bit like the December seasonal forecasts.  

image.thumb.png.f3a94c6038342b3f008d6809bc8bcde4.png

image.thumb.png.128902145a4ce9edd96204c75811a47f.png

 

Should also get us some regular precipitation started again...

 

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People don't understand weather.  Why aren't Strong La Nina's cold, if Strong El Nino's are warm? 

Strong El Nino's are more realistically the blend of the historical analogs of Weak-Moderate-Strong past events put together. Weak El Nino's are more random, or neutral, the cold signal is just a lack of many examples, as it is though somewhat showing the base-Nino state (Weak-Moderate-Strong). 

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1 hour ago, WxUSAF said:

Pretty good ensemble agreement on how the pattern develops going into Thanksgiving week with a much more Nino-like look to things.  Pattern shuffle starts with this big upper low crashing into the west coast around D8-9.

image.thumb.png.c35c62d6de1519643d04f2ef069033bb.png

image.thumb.png.94160d0a66e2e6b8d182abe07dfd6fd9.png

 

That serves to undercut the ridge in Canada and ridging expands over AK.  This doesn't look like a particularly cold pattern for us with a +AO/+NAO and the coldest air from the -EPO will dump out west first before coming east.  But it looks a lot more Nino-like and actually looks a fair bit like the December seasonal forecasts.  

image.thumb.png.f3a94c6038342b3f008d6809bc8bcde4.png

image.thumb.png.128902145a4ce9edd96204c75811a47f.png

 

Should also get us some regular precipitation started again...

 

This would be welcome. Could really use that precip.

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